Shock-resisting balance for watches



M y 0, 1941- w. SADOVSKY ETAL 2,242,712

SHOCK-RESISTING BALANCE FOR WATCHES Filed Aug. 28, 1939 3 r rm/ m %lfbrd Sadarsky JhnFPoweZl Patented May 20, 1941 SHOCK-RESISTING BALANCE FOR WATCHES Wolford Sadovsky and John F. Powell, San Antonio, Tex.; said Powell assignor to said Sadovsky Application August 28, 1939, Serial No. 292,300

2 Claims.

This invention relates to balance wheels for watches.

An object of the invention is the provision of a floating mounting for the staff of a balance wheel of a watch in which the jeweled bearings are resiliently mounted so that the staff may be moved in various directions during shocks and in which means is employed for limiting the floating movement of the staff.

Another object of the invention is the provision of a floating mounting for the balance staff of watches in which a pair of cooperating jewels is resiliently supported with the jewels being in contact with each other so that no oil may escape between said jewels and whereby all friction is eliminated between the surfaces of the jewels consisting of a balance hole jewel and a balance cap jewel.

A further object of the invention is the provision of a floating mounting for the balance staff of watches in which the jewels normally forming the bearings for the opposite ends of the staff are resiliently supported with means intermediate the ends of the staff to restrict excess side play so that during the side play of the staff the entire stress of any shock will be imparted to that portion of the staff of larger diameter, thereby taking the strain off of the reduced opposite ends of the staff supported by the jewels.

This invention will be best understood from a consideration of the following detailed description, in view of the accompanying drawing forming a part of the specification; nevertheless, it

is to be understood that the invention is not confined to the disclosure, being susceptible of such changes and modifications as define no material departure from the salient features of the invention as expressed in the appended claims.

In the drawing:

Figure 1 is a vertical section of a balance wheel mounting constructed in accordance with the principles of our invention,

Figure 2 is a top plan view of the same,

Figure 3 is a bottom plan view of the lower supporting plate, showing the dial face of the plate,

Figure 4 is a horizontal section taken along the line 4-4 of Fig. 1,

Figure 5 is a horizontal section taken along the line 5-5 of Figure 1,

Figure 6 is a horizontal section taken along the line 6-6 of Figure 1,

Figure 7 is a view in perspective of a resilient mounting for the jewels employed in the upper end of the staff,

Figure 8 is a view in perspective of the resilient mounting for the jewels located at the lower end of the staff,

Figure 9 is a fragmentary vertical section taken at right angles to the section shown in Fig. 1.

Referring more particularly to the drawing, l0 designates a balance bridge which is modified to accommodate the improvements defined herein. This plate is cut away at its lower end, as shown at H, to form a recess. This plate or bridge is provided with a passage 12 having an upstanding flange l3 which embraces said openmg.

The underface of the bridge is provided with a groove I4 which receives the free end 15 of a spring I 6. This spring, as shown at IT, is secured to an edge of the bridge l0 and has an inwardly curved portion Hi from which projects the free end I5. It will be noted that the spring 16 is bowed outwardly from the plate ID, as shown more particularly in Figs. 4 and 5, so that the spring may have free movement and out of contact with the side edges of the bridge.

A metal sleeve 20 is secured to the free end ill of the spring 16 and has its longitudinal axis in vertical alignment with the longitudinal axis of the opening I2. A jewel 2| is frictionally held within said sleeve, this jewel being known as the upper cap jewel working fiatly against the reduced end of a staff 23. A second jewel 24 is mounted below the jewel 2| and the inner ends of these jewels are in fiat contact with each other. The last-mentioned jewel is provided with a passage 25 which rotatably receives the upper end or" the staff 23.

A lower plate 28 is provided with a recess 21 which receives a spring 28. One end of this spring as shown more particularly in Fig. 3 is secured at 29 to the inner wall of the recess. The free end of the spring is curved, as shown at 30, and is secured to a sleeve 3| located axially within an opening 32 formed in the plate 26.

A jewel 33 is frictionally held within the sleeve SI and is known as the lower balance cap jewel which flatly receives the lower reduced end of the staff 23. A second jewel 35 is frictionally held within the sleeve 3| and the inner faces of the two jewels are in contact. The jewel 35 is provided with a passage 36 which receives the lower end of the staff 23 and this jewel also forms a bearing for the lower end of the staff as does the jewel 33.

Mounted on the staff is the usual balance wheel 40, a hair spring 4!, a roller table 42 and a safety roller 55.

A plate 45 is secured at 45 to the upper face of the lower plate 25 and is provided with an opening 41 through which passes the staff 23. This opening has a greater diameter than the portion of the staff that passes through said opening so that the staff will be free to move laterally but will be restricted in its lateral movement by the walls of said opening. It will also be noted that that portion of the staff which passes through the opening 4! is of greater diameter than the opposite ends of the staff where they are mounted in the respective jewels 24 and 35 so that the stronger portion of the staff will contact the walls of the opening 41. In view of this the smaller portion of the staff will be protected against too great a strain.

A second plate 55 has flanges secured by means of screws 5| to the underface of the balance bridge [0, as shown more particularly in Fig. 9. This plate is provided with a central opening 52 which is of greater diameter than the diameter of the balance staff 23, so that the staff 23 may have restricted movement similar to the restriction influenced upon the lower end of the staff by the walls of the opening 41.

The plate 5!] acts as a protector since it will engage the collet of the hair spring 4| and will limit the upward movement of the staff 23 to approximately two-tenths mm. and prevent the lower reduced end of said staff from being forced out of the jewel bearing when a shock is taken up by the watch.

It will be noted that all of the figures show enlarged views of the device but there is merely a clearance of approximately two-tenths mm. between the safety roller 55 and the plate 45. The clearance between the staff 23 and the walls of the openings 41 and 52 is approximately twotenths mm.

When a shock occurs the entire balance staff as well as the balance jewels are free to move until they have traveled approximately two-tenths mm. Then the staff is engaged by the protecting plate thereby eliminating any shock to the pivot or the jewels since the staff 23 has a floating mounting. When the shock is so imparted to the staff that it will move upwardly, the collet of the hair spring 41 will engage the underface of the protecting plate 50 and limit the upward movement thereof. When the staff moves in the opposite direction the shock will be taken up by the lower flat surface of the safety roller 55 which will engage the upper surface of the plate 45 and thus limit the downward movement. As has been stated, the walls of the openings 4'! and 52 limit the lateral movement of the staff to approximately two-tenths mm. This eliminates overbanking by keeping the roller and the pallet fork intact. These side walls also act upon the heavier portions of the staff to eliminate the strain on the pivots of the staff in their respective jewels.

We claim:

1. A shock-resisting balance for watches comprising a balance bridge, a plate located below the bridge, said bridge and plate having openings in vertical alignment, a bearing in each opening and spaced from the walls of the openings, a spring secured at one end to a side wall of the bridge, the bridge having at the front thereof a groove leading into the opening, said spring being curved around the side wall of the bridge and having the free end bent backwardly upon itself, located in the groove and projecting into the opening in the bridge, the free end of the spring where projecting into the opening being secured to the bearing in said opening, a second spring secured at one end to the plate, the other end being connected to the other bearing, a balance staff having the ends thereof mounted in the bearings and movable laterally and endwise with the resiliently mounted bearings, and means carried by the plate and means depending from the bridge for limiting lateral movement of the staff.

2. A shock-resisting balance for watches comprising a balance bridge, a plate located below the bridge, said bridge and plate having openings in vertical alignment, a bearing in each opening and spaced from the walls of the opening, a spring secured at one end to the side of the bridge at one end thereof. the bridge having a groove at the opposite end thereof leading into the opening therein. said snring being curved around the side wall of the bridge and having the free end bent towards the first-mentioned end and projecting through the groove and into the opening in the bridge. said free end being secured to the bearing in said opening, the plate having a groove leading into the opening in the plate, a second spring having one end secured to the plate at the inner wall of the groove and having the other end proiecting into the openin in the plate, said end being secured to the bearing in said opening, a balance staff provided with a balance wheel and havin the ends reduced and mounted in the bearin s movable laterally and endwise with the resiliently mounted bearings, a second plate having legs secured to the under face of the bridge for locating said plate adjacent the balance wheel, the second plate having an opening of larger diameter than the diameter of the portion of the staff passing therethrough to permit limited lateral play of the staff.

WOLFORD SADOVSKY. JOHN F. POWELL. 

